code: def test_powerset__len__():
      A = PowerSet(S.EmptySet, evaluate=False)
      assert len(A) == 1
      A = PowerSet(A, evaluate=False)
      assert len(A) == 2
      A = PowerSet(A, evaluate=False)
      assert len(A) == 4
      A = PowerSet(A, evaluate=False)
      assert len(A) == 16
  
file_path: sympy/sympy/sets/tests/test_powerset.py
imports: from sympy.core.expr import unchanged
  from sympy.core.singleton import S
  from sympy.core.symbol import Symbol
  from sympy.sets.contains import Contains
  from sympy.sets.fancysets import Interval
  from sympy.sets.powerset import PowerSet
  from sympy.sets.sets import FiniteSet
  from sympy.testing.pytest import raises, XFAIL
label_desc: Use image node_id 6 for calling a global function with example usage: test_powerset__len__() without return types